The RBD protein is part of the S protein of the new coronavirus COVID-19, and it is also a viral protein that can be used as the target of a recombinant protein vaccine against COVID-19. If the nucleic acid of COVID-19 virus wants to enter into human cells, the S protein of COVID-19 virus needs to bind to a specific receptor on human cells in order to infect the human body, and the RBD protein belongs to the key structure of the S protein. The newly developed recombinant protein vaccine targeting the RBD protein can destroy the RBD protein, so that the COVID-19 virus can not bind to the receptors on human cells and lose its infectious ability, which can prevent the virus from infecting the human body.